The invention relates to new and useful improvements in graphical user interfaces. More particularly, the invention relates to graphical user interfaces based on the xe2x80x9cWindowsxe2x80x9d(copyright) operating system in the xe2x80x9cpersonal computerxe2x80x9d class, which are widely used in the operation of computer programs. Such interfaces are known to offer virtually self-explanatory, intuitive control of computer programs even for inexperienced persons. One basis for the simplified operating characteristics consists of modern operating devices for computers, in particular the xe2x80x9cmousexe2x80x9d, which make the operating elements of graphical user interfaces particularly accessible.
In the area of industrial data processing, in particular the processing of production data in technical processes, such as by means of programmable controllers, the work of planning and designing process control programs is often carried out on something like a command code level. In this process, control instructions directed toward the inputs and outputs of the controller must be compiled in a special programming language, for example STEP 5 or STEP 7 language of the SIEMENS Company to form a so-called sequence control. Working with programming tools of this kind requires, at a minimum, prior knowledge and technical experience. Consequently this is possible at best for the operating personnel, for example, of production technology systems in which programmable controllers are employed.
The periodical xe2x80x9cindustriexe2x88x92elektrik+elektronik,xe2x80x9d Maschinenausrxc3xcstung+Automatisierung, Volume 1, January 1988, describes a system-independent programming system for controllers under the title xe2x80x9cSPS-Esperantoxe2x80x9d (incorporated herein by reference). This CAD/CAM software package is a graphical programmer tool for the programming of programmable controllers. In the process, the desired control task can be described by means of graphical modules, connecting lines, and comments. Other references directed to graphical systems include: U.S. Pat. No. 4,914,568 to Kodosky et al.; EP 0 549 510 A2 to Chang et al.; and Dellen et al., xe2x80x9cAutomated Code Generation from Graphical, Reusable Templatesxe2x80x9d, Proceedings of the 10th Digital Avionics Systems Conference, Oct. 14-17, 1991, each of which is incorporated herein by reference.
It is intended to make simple programmable controllers available to a broad circle of predominantly nonprofessional people. This group can use programmable controllers in many ways, such as in domestic installations. For them, however the use of conventional programming tools at a level similar to command code is not possible.
Accordingly, one object of the invention is to provide a graphical user interface for the programming of programmable controllers which even inexperienced users from the non-industrial sector can manage.
This and other objects are achieved by means of the graphical user interface of the independent claims. In particular, the invention provides both a graphical user interface and a method for programming a programmable controller. The interface includes a plurality of output interfaces and a plurality of programming windows assigned respectively to each of the output interfaces. Each one of the programming windows contains, first, a base node as a first graphical operating element for the output interface for that particular programming window as well as, second, at least one additional node as an additional graphical operating element for an input interface or for a group of linked interfaces of the programmable controller. The additional node includes at least one output branch line having a free end which is actuable to be coupled to the base node or to some further additional node by operating a graphical operating means such as a computer mouse. Coupling the free end of the output branch line of the additional node to the base node or to the further additional node establishes both a graphical and a control-system linkage between the coupled nodes. Further advantageous embodiments of the invention are the subject matter of the dependent claims.